JP2009511261A - Method and apparatus for regenerating a sorption dryer or cleaner - Google Patents

Abstract

The present invention relates to a method of regenerating an absorption or sorption dryer or cleaner. The method is by periodically heating the absorbing or adsorbing surface to a temperature at which the material to be absorbed or adsorbed is separated from the absorbing or adsorbing surface. The surface is kept fixed and is periodically exposed to the action of the heating means. Different parts of the surface can be heated continuously. That is, the active part of the heating means is moved along the surface. The invention also relates to an apparatus for performing this method, comprising heating means adapted to periodically expose the surface to the action. Such heating means may have a plurality of heating elements distributed and arranged along the surface and a control for alternately turning on and off the heating element switches.

Description

  The invention relates to a method according to claim 1 and an apparatus according to claim 6.

  Sorption dryers (dryers) or cleaners are used to dry or clean the media, especially by absorbing or adsorbing moisture or dirt present, which is a gas. Absorption means that when a material that draws moisture from a medium undergoes a physical or chemical change, it is absorbed, for example, into moisture. Adsorption is when the extracted moisture is simply held quickly on or at the surface of the material. Both phenomena are summarized below using the terms “sorption” or “sorption”. Application of this principle is, for example, drying of ambient air by sorbing the water present therein, for example in a temperature control. Another example is the removal of gases such as methane carried through a pipe system, by sorbing methane hydride present therein.

  Such drying or removal of the flowing gas is actually a two-step process. In the first process step, undesired substances, i.e. moisture or dirt, are dried by directing the gas along a material having a greater affinity for such a substance or a material having a lower vapor pressure than the gas itself. Or sorbed from the gas stream to be removed. In the second stage of the process, the sorbed material is relinquished to another medium, such as a released gas stream. In order to release the material from the sorbent material, the temperature must generally be significantly increased to raise its vapor pressure to a level above the vapor pressure of the discharged gas stream.

  In the example of air drying in temperature regulation, moisture is drawn from the air drawn from the outside, and this moisture is released again into the air drawn from the building and is exhaled to the outside. In order to draw water from the outside air, the air is guided along the surface to be covered with a layer of strong water-absorbing material such as silica gel. In order to release water again, air, for example (part of) exhaust, is heated to above the boiling point of water and guided along the adsorbent material. The water vapor can then escape and be taken up by the outgoing air stream. As a result, the adsorbent material is regenerated and again can draw a large amount of water from the air.

  In practice, a rotating wheel having a plurality of surfaces extending in the radial direction and covered with adsorbent material is utilized. The wheel is arranged between the supply duct and the discharge duct, its rotating shaft is parallel to the direction of air flow in the duct and the covered surface is partly rotating (during part of a rotation) through the supply duct and for the remaining part of the rotation through the discharge duct. During the passage of the supply duct, the covered surface draws moisture from the intake air and this water is released again during the passage of the discharge duct. In order to release as much water as possible from the adsorbent in a short time as the surface moves through the discharge duct, the wheel must be heated well above the boiling point of water, for example to 180 ° C. This requires a large amount of energy, not only to heat the water to the boiling point and above, but also to evaporate the water, especially because the heat of vaporization of water greatly exceeds its specific heat.

In order to drastically reduce the energy consumption of sorption dryers or cleaners, it has already been proposed to use so-called LCST (low critical melting temperature) polymers in the non-prepublished Dutch patent application No. 1029822. Has been. An LCST polymer is a polymer that is soluble in a material that is separated to a given temperature, critical dissolution temperature, or transition point, but is no longer soluble above this critical dissolution temperature, and the material that is absorbed is actually Will be repelled. The stability of the polymer in the dissolved state is ensured by a suitably chosen cross-linking agent. The transition point is clearly below the boiling point of the material to be separated. Because the transition point of LCST polymer is very low, for example on the order of 60-70 ° C., the polymer requires much less heating than is required in the case of conventional absorbent materials such as silica gel. Furthermore, the absorbed material does not need to be evaporated to be released from the LCST polymer, thus reducing the heat of vaporization for much more energy.
Dutch patent application number 1029822

  The present invention aims to provide a method for regenerating a sorption dryer or cleaner that is simpler to perform and requires less energy than the conventional regeneration methods described above. The present invention also aims to provide an apparatus for regenerating a sorption dryer or cleaner that is simpler and less expensive in construction and has a lower energy consumption than conventional regenerators. The method is achieved by a combination of the methods according to claim 1. The playback device according to the invention is characterized by the method as claimed in claim 6.

  Taking advantage of the fact that when a polymer with a low critical melting temperature is used, much less heat needs to be supplied to re-release the absorbed material, the present invention is a complex transfer. There is no need for moving constructions and is based on the insight that the regeneration phase can be performed at the same location as the absorption phase and simultaneously as desired. Thus, the surface with the absorbent material for regeneration can be kept fixed and periodically exposed to the action of the heating means.

  The active part of the heating means can move along the surface, so that different parts of the surface are regenerated at once. When regeneration occurs during normal operation of the sorption dryer or cleaner, the material for separation is withdrawn from the gas stream passing over a larger portion of the surface, while the material is released from the surface again in smaller quantities. A small portion of material is again taken into the gas stream, while a larger portion flows along the surface to the collection space. It is true that the overall effectiveness of the sorption dryer or cleaner is slightly reduced, but at the cost of significant simplification of structure and cost reduction.

  Desirably applied variants of the method according to the invention are described in the dependent claims 2-5, and preferred embodiments of the playback device are the subject of the dependent claims 7-12.

  The invention will now be elucidated on the basis of an embodiment with reference to the accompanying drawings.

  The sorption dryer or cleaner 1 is formed by a plate-like substrate 2 on which a layer of sorption (absorption or adsorption) material 3 is arranged. The plate-like substrate 2 defines a surface S that is a wall of a duct that supplies air to the space, for example. The sorption material 3 is a low critical solution temperature polymer, for example, polyoxazoline, poly (dimethylaminoethyl methacrylate) (pDMAEMa), or poly (N-isopropylacrylamide) (pNiPAAm). Alternatively, it is possible to envision a free-standing LCST polymer, thus eliminating the need for a separate material.

  The sorption dryer or cleaner 1 is further provided with heating means 4 to heat the polymer to its critical melting temperature. This means takes the form of a plurality of heating elements, here heating wires 5 etc. connected in a network. The heating means 4 further comprises a control 6 in which different parts of the network are switched on at one time. In this way, different parts of the heating means 4 are activated periodically and the active part of the heating means 4 moves along the surface S.

  The heating means 4 is arranged on a carrier 7 attached on the substrate 2. In the embodiment shown, the carrier 7 takes the form of a foil onto which the heating element 5 and the control 6 are printed, and is bonded between the substrate 2 and the layer of sorption material 3. As a result, a very small structure is obtained. This is possible because the sorption material 3 is ultimately an LCST polymer and only requires a low power supply.

  During use of the sorption dryer or cleaner 1, moist air MA, such as outside air, is blown or drawn through the duct using a fan, and each wall of this duct has a layer of sorption material 3 above it. Formed by the substrate 2 having As the moist air stream MA passes, the moisture M is drawn from it by the sorption material 3 and is quickly retained. The air stream A thus dried can be further cooled, etc., before leaving the duct and being supplied to the space.

  The sorbent material 3 must be regenerated by releasing the moisture again when it is taking a large amount of moisture that saturates. For this purpose, the sorption material is heated until it exceeds the critical melting temperature at which the polymer leaves the solution and moisture is rejected. When a low critical solution temperature polymer (LCST polymer) is used as the sorption material, this transition point occurs at a temperature clearly below the boiling point of water, such as about 60-70 ° C.

  The heating means 4 according to the invention is applied to a part of the sorption material 3 at a time above the critical melting temperature, while the rest of the material is maintained below this temperature and hence its normal Keeps the sorption effect. Under the influence of the control 6, a part S1 of the surface S that is close to the inflow side of the duct is first heated and regenerated, for example. A small amount of moisture V ′ is subsequently released to the passing humid air stream MA, which then passes along the remaining part of the surface S, with its moisture to the sorption material 3. Then let it dry and leave the duct. Most of the moisture V '' released by the heated part S1 flows down along the surface S and is subsequently collected.

  The control 6 switches on the other part of the network of heating wires 5 and the subsequent part S2 is heated and regenerated. The moist air stream MA is therefore first dried as it passes through the first part S1, and subsequently takes moisture V ′ from the sorption material 3 in the second part S2 and is further dried again by the remaining surface S. . Again, a greater part of the rejected moisture V ″ again flows down along the surface S.

  Thus, the entire surface can be regenerated in a short time by successively switching on and off parts of the network.

  The present invention has been described above on the basis of one embodiment, but is not limited thereto and it is obvious that it can be modified in many ways within the scope of the appended claims.

FIG. 4 is a perspective detail view with an exploded portion showing the structure of a sorption dryer or cleaner equipped with a regenerator according to the present invention. FIG. 2 is a schematic perspective view of a sorption dryer or cleaner having the regeneration device of FIG. 1 during regeneration of a first portion of the dryer or cleaner. FIG. 3 corresponds to the sorption dryer or cleaner of FIG. 2 during regeneration of the dryer or other portion of the cleaner.

Claims (12)

A method of regenerating a sorption dryer or cleaner having at least one sorption surface comprising:
The method is by periodically heating the sorption surface to a temperature at which the sorbed material is separated from the sorption surface;
The surface is kept fixed and periodically exposed to the action of the heating means,
A method characterized by that. Different parts of the surface are continuously heated,
The method of claim 1 wherein: At least an active portion of the heating means is moved along the surface;
The method according to claim 1 or 2, characterized in that During the regeneration of part of the sorption dryer or cleaner, the rest of the sorption dryer or cleaner continues to operate normally.
A method according to any one of claims 1 to 3, characterized in that The surface is heated to a temperature below the boiling point of the material separated therefrom;
A method according to any one of claims 1 to 4, characterized in that An apparatus for regenerating a sorption dryer or cleaner having at least one sorption surface comprising:
Means for periodically heating the surface to a temperature at which the sorbed material is separated from the surface;
The surface is kept fixed and the heating means is adapted to periodically expose the surface to its action;
A reproducing apparatus characterized by that. The heating means is adapted to continuously heat different portions of the surface;
The playback apparatus according to claim 6. The heating means has at least one active portion movable along the surface;
The playback apparatus according to claim 6 or 7, wherein The heating means has a plurality of heating elements distributed and arranged along the surface, and a control for alternately turning on and off the switches of the heating elements.
9. A playback apparatus according to claim 8, wherein The heating element is a heating wire connected in a network,
The reproducing apparatus according to claim 9. The heating element and the control are housed in a carrier connected to the surface,
The playback apparatus according to claim 9 or 10, characterized in that The heating means is adapted to heat the surface to a temperature below the boiling point of the material separated from the surface;
The playback apparatus according to claim 6, wherein the playback apparatus is a playback apparatus.

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